V.0.11.1 update

- Decreased the size of arena. - Changed the material of the walls. - Extended the max score from 5 to 8.

- Changes to Arena Mode :

- Increased the aggressiveness of AI. - Reduced the time interval between spawn of each powerups. - Reduced time rewinded.- Reworked on 'explosion' powerup. Picking up will now unleash fireballs into 4 directions.